1. Field of the Invention
This invention relates to improvements in a vehicular air conditioner of the type wherein cool air is introduced to air outlets through a passage bypassing a heater unit.
2. Description of the Prior Art
A variety of air conditioners for an automotive vehicle have been proposed and put into practical use. An example of such air conditioners is arranged as follows: The air conditioner includes an air conditioner duct in which a heater unit is disposed to heat air inducted into the duct. The duct is provided with air outlet openings opening into a passenger compartment of the vehicle. A bypass air passage is provided to connect upstream and downstream parts of the inside of the duct. The upstream part is located upstream of the heater unit, while the downstream part is located downstream of the heater unit. Accordingly, cool air not heated is introduced to the downstream part through the bypass air passage, bypassing the heater unit. Additionally, an air mixing door is controllably movably disposed near the heater unit and between the upstream and downstream parts in order to control the amount of air flow passing through the heater unit.
When the air mixing door is opened to supply air heated by the heater unit to the air outlet openings, and the bypass air passage is opened by opening a door movably disposed in the bypass air passage, the cool air will be introduced to the downstream part of the duct to be mixed with hot air heated by the heater unit. However, in this downstream part of the duct, insufficient mixing of cool air and hot air occurs. As a result, temperatures of air streams blown out through a plurality of air outlet openings become nonuniform, and the temperatures are caused to drop.